Question 258: Work, Energy and Power & Circular Motion

Question

A spherical body of mass 2 kg starting from rest acquires a kinetic energy of 10000 J at the end of $$\mathrm{5^{th}}$$ second. The force acted on the body is ________ N.

Accepted Answer

Let the force be $F$ so acceleration $a=\frac{F}{m}$
So displacement $S=\frac{1}{2} a t^{2}=\frac{F t^{2}}{2 m}$
So work done $W=F . S=\frac{F^{2} t^{2}}{2 m}$
From work energy Theorem
$\Delta K E=W$
$W=\frac{F^{2} t^{2}}{2 m}=10000$
$F=\sqrt{\frac{10000 	imes 2 	imes 2}{5^{2}}}$
$F=40 \mathrm{~N}$

Work, Energy and Power & Circular Motion

A spherical body of mass 2 kg starting from rest acquires a kinetic energy of 10000 J at the end of $\mathrm{5^{th}}$ second. The force acted on the body is ________ N.

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